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747 Gliding On No Engines - New Incident  
User currently offlineJulesmusician From , joined Dec 1969, posts, RR:
Posted (8 years 6 months 2 weeks 11 hours ago) and read 4427 times:

Following the incident over London where a 747 was running with very little engine power there have been recommendations that all pilots should be aware of their no power gliding profile of their aircraft - is this every done in simulators or if this did happen is it always down to a pilot's skill?

Incident is here:

http://www.aaib.gov.uk/cms_resources/N481EV%201-06.pdf

J

10 replies: All unread, jump to last
 
User currently offlineHAWK21M From India, joined Jan 2001, 31667 posts, RR: 56
Reply 1, posted (8 years 6 months 2 weeks 10 hours ago) and read 4415 times:

The commander carried out the descent using the autopilot in the vertical speed mode during which he became aware that the thrust levers were positioned in the “number six position”

What are the Thrust lever positions on a B747.

The crew discussed the anomaly of the forward thrust lever position and low engine power indications and recorded the engine EPRs as: ‘#1 eng 0.704, #2eng 1.124, #3eng 1.206 and #4eng 1.149’

Can EPR read less than 1.What stage are the EPR probes located on a B747

regds
MEL



Think of the brighter side!
User currently offlineReidYYZ From Kyrgyzstan, joined Sep 2005, 536 posts, RR: 0
Reply 2, posted (8 years 6 months 2 weeks 10 hours ago) and read 4409 times:

Quoting HAWK21M (Reply 1):
Can EPR read less than 1

Yes, at idle, on descent when the air is entering faster than the engine can push it out the ass end.

Quoting HAWK21M (Reply 1):
What stage are the EPR probes located on a B747

Depends which model engines.


User currently offlineHAWK21M From India, joined Jan 2001, 31667 posts, RR: 56
Reply 3, posted (8 years 6 months 2 weeks 8 hours ago) and read 4387 times:

Quoting ReidYYZ (Reply 2):
Yes, at idle, on descent when the air is entering faster than the engine can push it out the ass end.

Wouldn't that be momentary.
regds
MEL



Think of the brighter side!
User currently offlineFr8Mech From United States of America, joined Sep 2005, 5351 posts, RR: 14
Reply 4, posted (8 years 6 months 2 weeks 8 hours ago) and read 4374 times:

The EPR will less than 1.00 on descent.

The PT2 probe is located on the outboard side of the pylon. Left side for #1 & #2, right side for #3 & #4.

I've worked on the classics quite a bit, I believe I even worked N481EV, back in the day, and I've never heard of the '#6 throttle position'. He may have been referring to the index markings on the pedestal which are used by maintenance to mark throttle positions. 6 would have the throttle standing straight up, but nowhere near their max travel of about 11 or 12 (as I recall).

Interesting, according to the FDR graphic, the engines were stuck around the 1.15 - 1.21 range. This the 'bleed-shift' range (on the ground). As I recall, a JT9-7(x) that won't make power, but still has an increasing EGT, has not had 'bleed-shift'.

Bleed-shift is controlled on the engine independently of the other engines, except that one of th bleed controllers looks at air/ground logic. I just don;t remeber enough about chapter 75 on the JT9 to work it through my head any further.



When seconds count...the police are minutes away.
User currently offlinePhilSquares From , joined Dec 1969, posts, RR:
Reply 5, posted (8 years 6 months 2 weeks 6 hours ago) and read 4315 times:

The number 6 position is just the thrust lever markings on the throttle quadrant. They're used for rigging.

As a technique, I avoid using V/S because you can get slow very easy. In the older JT-9 engines, if you got slow it really took a good airflow through the fan to make sure the engine would accelerate. As Fr8Mech pointed out, there is a bleed shift issue and the older engines really suffer from those problems.


User currently offlineKJFK31L From United States of America, joined Jan 2006, 148 posts, RR: 0
Reply 6, posted (8 years 6 months 2 weeks 4 hours ago) and read 4250 times:

The report cited that the aircraft engines have a bleed air issue when the 747 is operating "light". It also indicates that the way to rectify such an issue is to power up the engine (to position 6). After 10 seconds the valve will reset itself and normal flight can be resumed.

Is this a common problem for 747-200 cargo aircraft operating with small cargo loads?

Matt



If it's not Boeing, I'm not going.
User currently offlinePhilSquares From , joined Dec 1969, posts, RR:
Reply 7, posted (8 years 6 months 2 weeks 2 hours ago) and read 4142 times:

Quoting KJFK31L (Reply 6):
Is this a common problem for 747-200 cargo aircraft operating with small cargo loads?

It's a common problem for all older 747-200s with PW powerplants. Another way to bypass the problem is to turn on the engine anti-ice.


User currently offlineHAWK21M From India, joined Jan 2001, 31667 posts, RR: 56
Reply 8, posted (8 years 6 months 1 week 6 days 8 hours ago) and read 3859 times:

Quoting PhilSquares (Reply 5):
The number 6 position is just the thrust lever markings on the throttle quadrant. They're used for rigging.

Any Pics on the Throttle Quadrant showing the Marks.
regds
MEL



Think of the brighter side!
User currently offlineFr8mech From United States of America, joined Sep 2005, 5351 posts, RR: 14
Reply 9, posted (8 years 6 months 1 week 6 days 6 hours ago) and read 3812 times:

Quoting HAWK21M (Reply 8):
Any Pics on the Throttle Quadrant showing the Marks.

Mel,

It's just a scale on the throttle quandrant. There is a prominent mark at 3.7, which is the part-power rig point. This is the point where the cable system, from the pylon, down to the JFC is rigged.


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Photo © Willem Honders




When seconds count...the police are minutes away.
User currently offlineHAWK21M From India, joined Jan 2001, 31667 posts, RR: 56
Reply 10, posted (8 years 6 months 1 week 6 days 4 hours ago) and read 3784 times:

Thanks for the Pic.  Smile
regds
MEL



Think of the brighter side!
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